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The formation mechanism of Cd–S–Se quantum dots (QDs) with a CdS/CdSe core–shell structure within a silicate glass system was investigated by monitoring the change in the first excitonic absorption peak of CdSe, CdS, and Cd–S–Se QDs as a function of the heat‐treatment (HT) duration. When a silicate glass containing QD formation components for CdSe or CdS single‐phased QDs was heat‐treated, CdSe QDs grew via Ostwald ripening, whereas CdS QDs hardly formed within the given silicate glass matrix. When the glass, including CdO, ZnSe, and ZnS, was utilized for the synthesis of Cd–S–Se QDs within the glass matrix, Cd–S–Se QDs were successfully formed and exhibited similar growth behavior to CdSe QDs during the initial stage of HT. The structural changes in the QD‐embedded glasses during HT were also monitored by Raman spectroscopy and discussed, and a possible formation mechanism of CdSe/CdS core–shell‐structured QDs within silicate glasses is suggested. [ABSTRACT FROM AUTHOR]

The thermal expansion coefficient ( TEC) of Ge-Sb-Se glass, within a compositional range suitable for molded lenses capable of transmitting long-wavelength infrared, was analyzed to assess compositional dependence. Unlike other thermal properties, eg, glass transition temperature and dilatometric softening temperature, which are correlated mostly with germanium content, the TEC turned out to behave most sensitively with selenium content. The thermal expansion behavior of this glass was evaluated based on two structural parameters: the mean coordination number and average bond energy ( ABE). It was verified that the relation between TEC and these structural parameters needs to be distinguished in terms of homopolar Se-Se bonds. Specifically, the TEC tends to decrease monotonically as the mean coordination number increases, and there are relatively small discrepancies between Se-sufficient and Se-deficient compositions. The TEC of the Se-sufficient glass appears to have a relatively well-defined correlation with the ABE: the TEC decreases as the ABE increases. However, a much weaker correlation between the TEC and ABE is observed in the Se-deficient glass. The observed thermal expansion behavior of this glass is delineated, with a particular focus on its connection to the structural role of the Se atoms. [ABSTRACT FROM AUTHOR]

In the present study, zinc‐molybdenum‐tellurite glasses are prepared and their thermal, thermo‐mechanical, viscous, and mechanical properties for mid‐IR molded glass lens applications are studied. From the thermal analysis, it is found that the glass transition temperature, onset crystallization temperature, and stability parameters slightly increase with an increase in ZnO content in both series of glasses. Thermal expansion coefficient decreases from 16.56 to 14.67 × 10−6 K−1 as the ZnO content increased from 10 to 30 mol%. For fixed 10 mol% of MoO3 content, Knoop hardness slightly decreases from 3009 to 2842 MPa as ZnO content increases from 10 to 30 mol% whereas it increases for 20 mol% of MoO3. The results indicate that the addition of ZnO and MoO3 contents into the tellurite glass system increases bridging oxygen contribution and in turn network compactness of tellurite matrix. [ABSTRACT FROM AUTHOR]